Thousands of students have demonstrated against Prime Minister Aleksandar Vucic's decisive win in a presidential election, claiming major irregularities in the campaign, including stifling the media, voter intimidation, and bribes.

For a sixth straight day, the students gathered in the Serbian capital of Belgrade on April 8 to protest Vucic's victory at the polls, where he garnered 55 percent of the vote on April 2 to win the presidency outright over 10 other candidates.

With music blaring in the background, the demonstrators blew whistles and banged pots as they taunted Vucic by calling him a thief and a tyrant while accusing him of stealing the election.

The number of protesters swelled in front the Serbian government's headquarters as hundreds of policemen and soldiers, who were holding a separate rally over low wages and poor living standards, joined the students.

"The times when politicians would turn the army and police against its people are over. The army, the police, and the people are in one place today," Veljko Mijailovic, the head of the police union, told the crowd.

Victory hands the 46-year-old Vucic and his Progressive Party, which has a majority in parliament, control over the entire legislative and governing process, and some critics have warned that could push the Balkan country back into the autocracy symbolized by former leader Slobodan Milosevic during his decade in power.

Once an ultranationalist, Vucic's rise to prominence in recent years came after he reinvented himself as a reformer who is committed to Serbia's drive toward European Union membership.

He has craftily strengthened his party's position through the ballot box, calling and winning two early parliamentary elections since 2014. While he once opposed integration with the 28-country bloc, he now pledges to prepare the nation of 7.3 million people for EU accession by 2019.

The protesters see Vucic as an autocratic leader and the Serbian Progressive Party as corrupt.

They have called for the government, along with top officials from the public broadcasters RTS and RTV, the Central Election Commission, and the regulatory Authority for Electronic Media, to step down.